Category Archives: Retrofits

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Polargy’s differentiation among containment manufacturers and contractors arises from our breadth of experience and depth of client understanding.

We bring to every project, whether large or small, not just attention to detail, precision design and product innovation, but years of diverse project experiences that allow us to visualize smart solutions and execute a project plan cleanly.

Big standardized new builds don’t have some of the “wild card” variables that small customized implementations often do, and while it’s gratifying to publicize large scale new construction containment deployments for Fortune 100 clients, we also enjoy sharing stories of modest retrofit projects brought online seamlessly. Every project, no matter how small, involves learning the client’s pain so we can solve it.

Whether you need just an aisle or literally a mile of airflow containment, Polargy is the call you make, because here’s what our clients say:

“The project went very well and we consider it a complete success, I wouldn’t change a thing. The outcome was exactly what we expected.”

Suffolk Public Schools in Virginia called Polargy when the air conditioning units in their ‘server room’ were over-tasked. The ‘server room’ at Suffolk was never designed for this use, it’s actually a converted storage room with 20 tons of A/C. Common but not ideal.

Director of Technology John Littlefield used rack heat extractors (photos below) but Trane HVAC engineers recommended containing the hot air and recooling it.

The goal of the containment project was typical: eliminate the rack heat extractors and improve the energy efficiency of the server room cooling. Littleton contacted Polargy and accomplished his goal quickly with a modest budget.

Since Polargy completed this project, the server room temperature is more stable, the cooling system runs more efficiently with less impact on the rest of the building, and the next step is to add an aisle-end door. The Polargy single-sliding door will look great.

There is some confusion in the marketplace regarding changing fire safety regulations and materials deployed in the data center as airflow containment. To help clear things up, I prepared a technical briefling titled “New NFPA Standards Explained” which I have been presenting at AFCOM regional meetings. For the benefit of the many people who may be suffering a bout of this confusion and missed my presentations, I’ve provided my slides.

If you’re planning a containment project, whether retrofit or new construction, and want to be sure you’re interpreting fire codes correctly, give us a call. Polargy is the trusted partner in data center containment to get your job done right the first time, on time and on budget.

N+1 redundancy is a system design best practice because equipment failure happens; we expect it and we plan around it. In the case of data center cooling, we expect a CRAC to go down at some point, and with an N+1 system design we have a spare CRAC to fall back on. A major problem with this aggregate view of cooling is risk of starving a cold aisle when changing the CRAC lineup or as a result of CRAC failure, and this risk is amplified with cold aisle containment. Fortunately, we can easily and cost-effectively manage this risk with ‘air-mover’ fan tiles in the cold aisles.

Time and time again we hear operators talk about how changing the CRAC lineup causes cooling airflow problems. Most of these comments come from legacy sites, though we’ve also heard them from new data centers. Interestingly, many operators fail to connect the dots between this airflow problem and N+1 redundancy. Many operators have a particular CRAC unit they don’t dare turn off and yet they assume their spare CRAC unit gives them N+1 redundancy. In our experience, about a quarter of small-to-medium data centers suffer from this false assumption; their N+1 redundancy is on paper only.

The Balancing Act

I can’t tell you how often I’ve heard comments like, “We need to keep CRAC Unit #3 on all the time or the room overheats” or “When we take CRAC #6 down for maintenance we get hotspots on the north side.” These problems are indicative of typical airflow behavior in raised floor environments:

CFM into an aisle is highly dependent on under floor pressure and obstructions.

CFM into an aisle is largely driven by the closest CRAC (the ‘CRAC of Influence’).

Changing the CRAC lineup creates large swings in CFM delivered to an aisle.

Total air supply may be sufficient but local supply may not (the ‘Distribution Problem’).

With these understandings, one can easily see how a change in the CRAC lineup can cause under floor pressure to change enough to introduce significant risk of an adverse thermal event.

When we think of cooling sufficiency, thermal safety and preventing problems, it’s in terms of normal operating conditions and failure conditions, and both scenarios are highly dynamic. In normal operating conditions we deal with routine changes in cooling demand and supply throughout room while the CRAC lineup remains unchanged. In failure conditions, we deal with a large change in under floor pressure when one CRAC goes offline and a spare unit takes over.

In normal operating conditions, routine changes in airflow demand and supply create risk of falling out of balance and starving a cold aisle. Cooling demand varies at the rack level, aisle level and room level, and can fluctuate either quickly or slowly. For example, a researcher who kicks off a large computational job can quickly heat up one or more racks of number-crunching servers. Or an IT guy swaps a 10kW rack in where a 2kW rack had been, but forgets to mention it to the facilities crew. These changes in demand for cooling create a less obvious change in cooling supply. When cooling demand in one aisle increases, the change in air consumption will affect the supply available to adjacent aisles. Such demand and supply changes during normal operations affect under floor pressure and can result in an aisle with localized low pressure.

In failure conditions, loss of a CRAC unit and replacement with the N+1 redundant unit will cause a change in under floor pressure. Because cooling supply to an aisle is most influenced by the nearest CRAC, and depending on the specifics of the under floor situation, a change in CRACs can result in a low-pressure zone and under-supplied aisles. There may be sufficient cooling supply, but because of the Distribution Problem, there is localized low pressure and even aisle starvation. In this case, even if the N+1 redundant CRAC unit comes online as planned, the best we can say is that the site has only partial redundancy.

Fixing With Fans

Fortunately, achieving true N+1 redundancy and mitigating cooling failure risk we’ve described can easily be achieved with active fan tiles that locally modulate airflow. Raised floor fan tiles, such as the Frost-Byte™ Raised Floor Fan Tile, vary speed to deliver cold air to the aisle based on sensed temperature or pressure differential versus a target setpoint. With several of these “air-mover“ tiles in a contained cold aisle, the right amount of cold air is supplied to mitigate thermal risk from inevitable cooling demand and supply changes during both normal operations and failure conditions.

These active fan tiles are built with a matrix of high performance variable speed DC fans in an aluminum enclosure attached to a standard 60% raised floor tile. Commonly, a temperature sensor mounted on the face of server racks controls the fans. Alternatively, sensors that measure pressure differential between inside and outside the contained cold aisle control the fans. This fan tile architecture auto-balances the cold aisles, eliminating starvation risk and improving thermal safety.

Other Fan Tile Benefits

An alternative solution to balancing cooling demand and supply is simply to over-supply an aisle, but with today’s emphasis on energy efficiency, the days of oversupplying are largely over. In fact, energy efficiency is the major factor driving the adoption of aisle containment, though even with containment, we sometimes still see oversupply due to balancing challenges. With active fan tiles, these remaining oversupply scenarios can be reduced or eliminated, yielding the full efficiency promise of cold aisle containment.

Additionally, by auto-balancing with active fan tiles, operators achieve labor savings from the elimination of routine manual balancing. The days of walking the room and swapping out perforated tiles are over. Active fan tiles eliminate the need to analyze aisles with a balancing hood (aka: flow balometer) to ensure the CFM in the cold aisle more than matches the IT load in that aisle. Likewise, because conditions in the room and aisles are so dynamic, Computation Fluid Dynamics (CFD) analysis for balancing purposes becomes obsolete since CFD provides a historical ‘snapshot’ of airflow that may no longer be relevant.

Lastly, if active fan tiles are powered through a UPS, they can ensure greater uptime if cooling is completely lost. In a catastrophic cooling failure condition, the under floor plenum holds a cool air reservoir, though without air pressure or air flow. Fan tiles running on UPS backup can continue to deliver and circulate cold air from within this chilled plenum. Testing demonstrates that supply air temperature through the fan tiles remained steady for more than 10 minutes even with all CRACs off.

“We’re thrilled to launch a site designed for the professionals we work with so closely.” —Cary Frame

The new website features ready access to educational materials about containment, including design files for industry-leading PolarPlex™ containment. CAD, BIM and SKP (SketchUp) design files for PolarPlex are freely downloadable, making it easier for designers (ex: architects and engineers) to speed up new construction and retrofit project design.

Polargy provides premium airflow management accessories and expert professional services with their world-class solutions for each of the six fundamental containment topologies.

The new site also improves access to brochures and videos developed to help educate the trade on containment best-practices as containment adoption continues to soar.

If you spend as much time with customers as Polargy does, you become very familiar with the details and nuance of their challenges. This means we’re often positioned to solve—and even anticipate—customer problems with innovative containment solutions.

Almost more importantly (for business), staying close to a large number of varied customers allows Polargy to recognize common pain points across the market.

In the PolarDam case, our customer needed to close about a hundred air gaps of varying sizes, and it was clear that brush grommets weren’t going to get the job done. The high cost of brush grommets alone made them a bad option but they also just didn’t work.

Together with the customer, we developed a simple, customizable air gap sealing solution that beats brush grommets every time in terms of fit, cost and flexibility. It was clear to us immediately that the same air gap challenges this customer had were common to data centers everywhere.

“Everyone knows that air leakage reduces data center cooling efficiency. The best kept secret for sealing air gaps is PolarDam Air Dam Foam.”

And here’s a little gallery of some of the most popular PolarDam applications:

Normal cable cutouts where you could use a brush grommets (but prefer PolarDam’s far lower cost)

Odd-shaped or obstructed cutouts that no brush grommet will fit

2-post racks, either on top or through the floor

Blanking inside racks when you’re blanking off an entire 1U or 2U (or more) but especially when you’re running cables out through the front of the rack. Try to do that with a rigid blanking panel.

Pipe penetrations through a floor or near a wall…

…and there are so many more.

The important thing to remember is that PolarDam closes all these air gaps in seconds. No tools, no measuring, no messy drilling. Just tear it to the perfect size and push it into place with your hands.

Last week we announced a new partnership with Australia-based rack manufacturer Rack Technologies. Rack Tech will distribute, sell and service Polargy’s data center containment solutions in the Australia/New Zealand region. This partnership is an important step for Polargy as we expand our global reach.

Rack Tech manufacturers 19” and 26” specialty rack systems and accessories for the communications, electronic and security industries. Founded in 1990 and acquired by Preformed Line Products (PLP) in 2000, Rack Tech has now grown into one of the region’s largest manufacturers of enclosures and accessories.

We’re thrilled to partner with Rack Technoligies. Fred Garnier (Polargy’s VP of Channel Sales) said in the press release:

“Rack Technologies is an ideal partner for Polargy in Australia. Their local design, manufacturing and installation expertise is the perfect extension of Polargy’s US manufacturing, sales and service operations. Their strong customer support orientation will help ensure optimal outcomes for customers of all types and sizes.”

Together, we are well positioned to reduce operating costs for large and small data centers across Australia, reflecting growing environmental awareness and responsibility in the data center industry.

Airflow management and containment solutions have rapidly become an operating best practice in both new construction and legacy data centers worldwide, and under this agreement, we can continue promoting best-practices in hot- and cold-aisle containment domestically and internationally.

We all continue to struggle with containing “side-to-side” air on the 6500s. We stumbled upon this fix last year in San Jose, CA. The owner reports sufficient air supply with this simple hose and manifold set up.

Cold Air Piped into Cisco 6500s

Is that my dryer exhaust hose?

Here is a little less sophisticated approach on a newer switch at a site in New Jersey.

Power is expensive in the Caribbean so data center efficiency is all the more important. Modern Power and Cooling Technology Limited successfully designed and implemented a cold aisle containment solution at the state of the art tier 3 Digicel Collocation Facility at Caymans using Polargy’s Aisle Containment System with the one of a kind “drop away” panel. A few classic site conditions were columns down the aisles, uneven aisle ends, and a single sided aisle. What is most impressive is that the design was done locally by Modern Power and they installed the system with no difficulties.

The site, near Denver, was purpose built so Xcel Energy could just take a before and after meter reading for the entire building. The IT load did not really change over the course of the project, so the reduction was attributed to the shutting off of 39 CRAC units out of 70 units running. This reduction was measured at 435kW, or about 11kW per CRAC unit. These CRAC units were the old AirFlow brand and the per unit reduction was higher than anticipated but we double checked the meter readings and verified the constant IT load (via the UPS) to confirm the numbers.

Old Airflow CRAC Badge

The containment was a combination of cold aisle containment, under floor partitions, and CRAC unit extensions. PUE before was 2.0, after it was 1.8.

Polargy helped calculate the ROI. The project’s net costs were $400K ($569K less $169K). The 435kW savings yielded $225K annually (power rate is about 6 cents per kWh). This results in a project payback period of 1.6 years.